From: "Mukunda,Vijendar" <vijendar.mukunda@amd.com>
To: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>,
broonie@kernel.org
Cc: alsa-devel@alsa-project.org, Basavaraj.Hiregoudar@amd.com,
Sunil-kumar.Dommati@amd.com, Mastan.Katragadda@amd.com,
Arungopal.kondaveeti@amd.com, mario.limonciello@amd.com,
Liam Girdwood <lgirdwood@gmail.com>,
Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.com>,
Syed Saba Kareem <Syed.SabaKareem@amd.com>,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH V2 5/9] ASoC: amd: ps: add support for SoundWire DMA interrupts
Date: Wed, 31 May 2023 12:58:46 +0530 [thread overview]
Message-ID: <af5b0669-2621-7fce-358c-76dca7b521c5@amd.com> (raw)
In-Reply-To: <017abf89-a1aa-0c85-e244-a56c05b7c6e2@amd.com>
On 24/05/23 13:15, Mukunda,Vijendar wrote:
> On 23/05/23 20:30, Pierre-Louis Bossart wrote:
>> On 5/23/23 02:36, Mukunda,Vijendar wrote:
>>> On 22/05/23 23:42, Pierre-Louis Bossart wrote:
>>>> On 5/22/23 08:31, Vijendar Mukunda wrote:
>>>>> Initialize workqueue for SoundWire DMA interrupts handling.
>>>>> Whenever audio data equal to the SoundWire FIFO watermark level
>>>>> are produced/consumed, interrupt is generated.
>>>>> Acknowledge the interrupt and schedule the workqueue.
>>>> It would help to explain why a work queue is needed is the first place,
>>>> as opposed to handling periods in the interrupt thread.
>>> For SoundWire DAI link, we are setting nonatomic flag to true.
>>> If we return period elapsed from hard irq handler instead of workqueue,
>>> soft lock up is observed during stream closure.
>>>
>>> We can use interrupt thread as well. To have a symmetry with
>>> SoundWire manager work queues, we have used workqueue for
>>> DMA interrupts.
>> Oh, I completely missed the model here.
>>
>> If you are using the bottom half/hard irq handler to read status
>> information, the natural thing to do would be to have an irq thread, no?
>>
>> Not sure I see the benefit of aligning with the manager work queues -
>> unless it makes your life simpler to avoid race conditions with
>> cancel_work_sync()?
> We can implement request_threaded_irq() and move the handling of
> DMA interrupts to thread function whereas we need to handle SoundWire
> manager interrupts in top half only. Reason as follows.
>
> As per our design, we are not masking the interrupts in top half and
> restoring mask after thread execution like Intel and
> our IP supports line based interrupts. If we move SoundWire manager
> interrupt handling to thread function, we have observed interrupts are
> reported but not handled properly due to thread execution is in progress
> sometimes.
> we will add comments for this design constraint in the code if we have to
> go with threaded_irq implementation.
>
> @Bossart: we are waiting for your reply.
>>>>> +static void acp63_sdw_dma_workthread(struct work_struct *work)
>>>>> +{
>>>>> + struct acp63_dev_data *adata = container_of(work, struct acp63_dev_data,
>>>>> + acp_sdw_dma_work);
>>>>> + struct sdw_dma_dev_data *sdw_dma_data;
>>>>> + u32 stream_index;
>>>>> + u16 pdev_index;
>>>>> +
>>>>> + pdev_index = adata->sdw_dma_dev_index;
>>>>> + sdw_dma_data = dev_get_drvdata(&adata->pdev[pdev_index]->dev);
>>>>> +
>>>>> + for (stream_index = 0; stream_index < ACP63_SDW0_DMA_MAX_STREAMS; stream_index++) {
>>>>> + if (adata->sdw0_dma_intr_stat[stream_index]) {
>>>>> + if (sdw_dma_data->sdw0_dma_stream[stream_index])
>>>>> + snd_pcm_period_elapsed(sdw_dma_data->sdw0_dma_stream[stream_index]);
>>>>> + adata->sdw0_dma_intr_stat[stream_index] = 0;
>>>>> + }
>>>>> + }
>>>>> + for (stream_index = 0; stream_index < ACP63_SDW1_DMA_MAX_STREAMS; stream_index++) {
>>>>> + if (adata->sdw1_dma_intr_stat[stream_index]) {
>>>>> + if (sdw_dma_data->sdw1_dma_stream[stream_index])
>>>>> + snd_pcm_period_elapsed(sdw_dma_data->sdw1_dma_stream[stream_index]);
>>>>> + adata->sdw1_dma_intr_stat[stream_index] = 0;
>>>>> + }
>>>>> + }
>>>> I am not clear on the benefits of the workqueue which only tests a flag
>>>> that's set ...
>>> In top half, we are checking all stream irq mask and setting
>>> corresponding stream id index in interrupt status array when dma
>>> irq is raised.
>>>
>>> Our intention is to handle snd_pcm_period_elapsed in process context.
>>> if the flag is set, call the period elapsed for the substream based on stream
>>> id in work queue.
next prev parent reply other threads:[~2023-05-31 7:24 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20230522133122.166841-1-Vijendar.Mukunda@amd.com>
2023-05-22 13:31 ` [PATCH V2 1/9] ASoC: amd: ps: create platform devices based on acp config Vijendar Mukunda
2023-05-22 16:16 ` Pierre-Louis Bossart
2023-05-23 6:25 ` Mukunda,Vijendar
2023-05-23 14:29 ` Pierre-Louis Bossart
2023-05-24 7:02 ` Mukunda,Vijendar
2023-05-22 13:31 ` [PATCH V2 2/9] ASoC: amd: ps: handle SoundWire interrupts in acp pci driver Vijendar Mukunda
2023-05-22 16:26 ` Pierre-Louis Bossart
2023-05-23 6:49 ` Mukunda,Vijendar
2023-05-23 14:34 ` Pierre-Louis Bossart
2023-05-24 7:01 ` Mukunda,Vijendar
2023-05-22 13:31 ` [PATCH V2 3/9] ASoC: amd: ps: add SoundWire dma driver Vijendar Mukunda
2023-05-22 16:34 ` Pierre-Louis Bossart
2023-05-23 7:11 ` Mukunda,Vijendar
2023-05-23 14:48 ` Pierre-Louis Bossart
2023-05-24 11:37 ` Mukunda,Vijendar
2023-05-25 11:43 ` Mukunda,Vijendar
2023-05-22 13:31 ` [PATCH V2 4/9] ASoC: amd: ps: add SoundWire dma driver dma ops Vijendar Mukunda
2023-05-22 16:39 ` Pierre-Louis Bossart
2023-05-23 5:41 ` Mukunda,Vijendar
2023-05-22 13:31 ` [PATCH V2 5/9] ASoC: amd: ps: add support for SoundWire DMA interrupts Vijendar Mukunda
2023-05-22 18:12 ` Pierre-Louis Bossart
2023-05-23 7:36 ` Mukunda,Vijendar
2023-05-23 15:00 ` Pierre-Louis Bossart
2023-05-24 7:45 ` Mukunda,Vijendar
2023-05-31 7:28 ` Mukunda,Vijendar [this message]
2023-05-31 13:53 ` Pierre-Louis Bossart
2023-06-05 11:24 ` Mukunda,Vijendar
2023-05-22 13:31 ` [PATCH V2 6/9] ASoC: amd: ps: add pm ops support for SoundWire dma driver Vijendar Mukunda
2023-05-22 18:20 ` Pierre-Louis Bossart
2023-05-23 10:53 ` Mukunda,Vijendar
2023-05-23 15:03 ` Pierre-Louis Bossart
2023-05-22 13:31 ` [PATCH V2 7/9] ASoC: amd: ps: enable SoundWire dma driver build Vijendar Mukunda
2023-05-22 13:31 ` [PATCH V2 8/9] ASoC: amd: update comments in Kconfig file Vijendar Mukunda
2023-05-22 13:31 ` [PATCH V2 9/9] ASoC: amd: ps: Add SoundWire specific checks in pci driver in pm ops Vijendar Mukunda
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